Difference between two lists

I Have two generic list filled with CustomsObjects.

I need to retrieve the difference between those two lists(Items who are in the first without the items in the second one) in a third one.

I was thinking using `.Except()` was a good idea but I don't see how to use this..
Help!

If both your lists implement IEnumerable interface you can achieve this using LINQ.

list3 = list1.where(i => !list2.contains(i));

var third = first.Except(second);

(you can also call `ToList()` after `Except()`, if you don't like referencing lazy collections.)


The `Except()` method compares the values using the default comparer, if the values being compared are of base data types, such as `int`, `string`, `decimal` etc.

Otherwise the comparison will be made by object address, which is probably not what you want... In that case, make your custom objects implement `IComparable` (or implement a custom `IEqualityComparer` and pass it to the `Except()` method).

Since the Except extension method operates on two IEumerables, it seems to me that it will be a O(n^2) operation. If performance is an issue (if say your lists are large), I'd suggest creating a HashSet<CustomsObject> from list1 and use HashSet's ExceptWith method.

bit late but here is working solution for me

var myBaseProperty = (typeof(BaseClass)).GetProperties();//get base code properties
var allProperty = entity.GetProperties()[0].DeclaringType.GetProperties();//get derived class property plus base code as it is derived from it
var declaredClassProperties = allProperty.Where(x => !myBaseProperty.Any(l => l.Name == x.Name)).ToList();//get the difference

In above mention code I am getting the properties difference between my base class and derived class list

You could do something like this:

var result = customlist.Where(p => !otherlist.Any(l => p.someproperty == l.someproperty));